Black & Decker LST136W Review

product image of Black & Decker LST136W 40V Max Lithium String Trimmer

Our rating: 4.5 stars Very good  

Customer rating: 4800+ reviews

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* including battery and charger

The Black & Decker LST136W is our most recommended cordless weed eater – and also one of the most popular on the market. Easy to handle, lightweight and with solid power and battery time.

  • Power adjustment dial
  • Overall performance, power, battery
  • Even for people above 6ft
  • none significant
Key specifications:
  • Edger: yes
  • Weight: 6.8 lbs
  • Battery time (according to users): 40/20 minutes (low/high speed)
  • (more specifications)

Black & Decker 36 Volt Weedeater/Trimmer/Edger – Product Review

Note: Some of the videos actually show the older 36V machine, but basically – the battery is the only difference.

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trimming overgrown grass near fenceThe LST136W shares all the advantages of cordless weed whackers – complete freedom of movement, no messing with the cord (and winding it up after trimming) or switching outlets. Also no maintenance, noise or vibrations typical for gas trimmers.

It is lightweight and well balanced, even a child or smaller woman won’t get tired after 30 minutes of use, and also easy to start – you just push the safety switch and then the trigger.

Power and line feeding

With the increased voltage, cordless trimmers are getting more and more powerful – don’t expect the performance of a gas machine (there is still a significant gap); however, for a regular lawn it is pretty adequate.

A great feature is the power command dial – you can choose between 6 different speeds (ranging from 6500 to 8500 RPM) which is very useful for preserving the battery life. For example you’ll trim most of your yard on the low-middle setting and bump it up to number 6 just for the tough weeds or higher grass.

Power command dial

The trimmer uses autofeed to advance the line, so no bumping is required – and the mechanism works well.


The LST136W is part of the Black&Decker’s new 40V Max lineup – the good news is that these tools are compatible with the older 36V battery so if you have some machines from the older lineup, you probably already have some spare batteries for your new trimmer.

Very important point is of course the battery working time – you can expect about 20 minutes of work on high setting or 40 minutes on low/medium speed. So if you need to trim a lot of thick weeds, buying a spare battery is recommended. It also features a light indicator so you know approximately how much power you have left.

The battery can be easily removed with the click of a button and it takes less than one hour to fully recharge. So with a spare battery it’s more or less possible to create a trimming routine with one battery working, the other recharging – and then switching them and so on.

Edger function

Edger and adjustments

It’s rather a standard for cordless weed whackers to be equipped with an edger adjustment and this machine is no exception. The head can be easily rotated 180-degrees to enable edging tasks and a metal guide is also present. There are no guide wheels, but that’s not a big drawback.

Other adjustments include setting the shaft height and angle of the handle, both tool free. Particularly the height adjustment is really handy as you can set it to the exact height you need to avoid back pain – and the shaft extends quite a lot, this tool is easy to use even if you are more than 6ft tall!

Only the angle of the head is not adjustable, so for maintaining hard to reach areas it’s not as convenient as the Greenworks 21332 or WORX units.

Conclusion:  If you want quality and lightweight string trimmer that is very easy to use and offers a decent power, Black & Decker LST136W is the right choice for you. We highly recommend it.

However, even with the 40V battery it is still intended mainly for lighter/medium jobs – for heavy trimming gas machines (or cordless with brushless motor) are the way to go.

>> Read more or buy the Black & Decker LST136W here

edging a walkway      changing the spool


  • Battery time (according to users): 40/20 minutes (low/high speed)
  • Battery power indicator: yes
  • Weight: 6.8 lbs
  • Cutting swath: 13″
  • Line: 0.065 single string
  • Feeding: autofeed
  • Warranty: Full 3-Year Home Use
  • Includes: 1 battery, charger, 1 spool

(compare with others)

Frequently asked questions:

How to assemble it?
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How to change the line spool?
   Show Video
How should I treat the battery to ensure maximum lifetime?

Always store the batteries inside your house in reasonable temperatures – never leave them on direct sun or outdoors during winter! Black and Decker also advises to recharge the battery as soon as it is out of power.

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What is included in the package?

The weed eater itself, 1 battery, charger and 1 spool.

Are there any accessories I should buy?

We recommend getting the 3 spool replacement package and if you have a larger yard, consider buying a spare battery.

Also, if you need a cordless blower as well, you can buy them together (select the “string trimmer + sweeper” option) and save a considerable amount of money. The downside is that you’ll ger a slower charger with this combo.

Is there any maintenance needed?

No, the motor is an enclosed unit so no maintenance is required. Just ensure a proper care to the battery (see above) and clean the machine from dead grass occasionally.


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